IDEHU   05542
INSTITUTO DE ESTUDIOS DE LA INMUNIDAD HUMORAL PROF. RICARDO A. MARGNI
Unidad Ejecutora - UE
artículos
Título:
Activity modulation of microbial enzymes by Lama glama Heavy Chain polyclonal antibodies during in vivo immune responses”
Autor/es:
ALEJANDRO FERRARI; FEDERICO SIMÓN WEILL; MARIELA LAURA PAZ; ELIANA MAITÉN CELA; DANIEL HORACIO GONZÁLEZ MAGLIO; JULIANA LEONI
Revista:
RESEARCH IN VETERINARY SCIENCE
Editorial:
ELSEVIER SCI LTD
Referencias:
Año: 2009
ISSN:
0034-5288
Resumen:
In the last decades, the knowledge about the structure and function of antibodies (Abs) has shown a dramatic progress. One of the most significant discoveries in this area is the existence of functional Ab isotypes devoid of light chains (Heavy Chain Antibodies, HCAbs) in camelids. It was found that recombinant variable fragments (rVHHs) of these Abs show an unusual resistance to physicochemical aggressions, as well as a special ability to interact with epitopes that are cryptic for conventional Abs. It has been usually assumed that in vivo raised polyclonal HCAbs (pHCAbs) should behave in a similar fashion than rVHHs, but this assumption has not been tested. The present work was aimed to evaluate the interaction of pHCAbs and their pepsic fragments (VHH’2) with two microbial enzymes that have their active sites buried in a cleft, and to analyze if this interaction differs from that of rVHHs and conventional Abs. The results indicate that pHCAbs and VHH’2 are as thermostable as rVHHs. Nevertheless, pHCAbs not only failed to inhibit the enzymes, but also activated one of them, probably by means of an allosteric modulation or a transition-state stabilization. Therefore, a reasonable doubt is set on the validity of extrapolating the features from rVHHs to pHCAbs. Furthermore, the relative contribution of pHCAbs to the serum ELISA titre and modulation capacity, was proven to be secondary when compared to that of IgG1, highlighting the requirement to consider the different subisotypes when designing and performing clinical tests and veterinary sanitary policies.